File Coverage

blib/lib/Astro/SolarParallax.pm

Criterion	Covered	Total	%
statement	9	25	36.0
branch			n/a
condition	0	3	0.0
subroutine	3	5	60.0
pod	2	2	100.0
total	14	35	40.0

package Astro::SolarParallax;

#use 5.008003;
use strict;
use warnings;
use Math::Trig;

our $VERSION = '0.04';


=head1 NAME

Astro::SolarParallax - Find the Solar Parallax from Venus Transit

=head1 SYNOPSIS

  use Astro::SolarParallax::Observer;
  use Astro::SolarParallax;
  use Geo::Coordinates;
  my $obs1 = new Geo::Coordinates;
  my $obs2 = new Geo::Coordinates;
  $obs1->latitude(78.20); # Longyearbyen
  $obs1->longitude(15.82);
  $obs2->latitude(13.7307); # Bangkok
  $obs2->longitude(100.521);
  my $observer1 = Astro::SolarParallax::Observer->new($obs1);
  my $observer2 = Astro::SolarParallax::Observer->new($obs2);
  # Longyearbyen
  $observer1->contacttime(1, "07:17:47");
  $observer1->contacttime(4, "13:21:00");
  # Bangkok
  $observer2->contacttime(1, "07:13:07");
  $observer2->contacttime(4, "13:20:36");
  my $measurement = Astro::SolarParallax->new($observer1, $observer2);
  print $measurement->AU(1,4);


=head1 DESCRIPTION

This module is intended to be used to compute the solar parallax from planetary transits. Specifically, in the current implementation, it makes use of a method developed by F. Mignard, and is limited to the transit of Venus on 2004-06-08.

It has a object oriented interface.

=over

=item C

This is the constructor of this class, it takes as argument two observers, that is, two objects of the L class.

=cut

sub new {
    my $that  = shift;
    my $obs1 = shift;
    my $obs2 = shift;
    my $class = ref($that) || $that;
    my $self = {
	OBS1 => $obs1,
	OBS2 => $obs2,
    };

    bless($self, $class);
    return $self;
}

=item C

This method will return the distance to the sun in kilometers, based on the measurements done by the two observers given to the constructor. It takes as argument and array containing the number of the contact points, in ascending order.

The constraints in the L apply.

=cut


sub AU {
    my $self = shift;
    my @contacts = @_;
    my $deltatref = ${$self}{'OBS2'}->deltatref(@contacts)
                  - ${$self}{'OBS1'}->deltatref(@contacts);
    my $deltatobs = ${$self}{'OBS2'}->deltatobs(@contacts)
                  - ${$self}{'OBS1'}->deltatobs(@contacts);
  return (149.60 * 1000000 * $deltatref->seconds / $deltatobs->seconds);
}


1;
__END__